- cardiovascular disorders that might be aggravated by participation in the study: hypotension (SBP: < 100 mmHg), bradycardia (heart rate < 60 /min), severe atrioventricular block (Type II or III), severe hypertension (SBP: > 160 mmHg; DBP: > 100 mmHg), myocardial infarction, history of chest pain and admission to ED for chest pain;